"filthy," 1590s, in reference to Augean stable, the cleansing of which was one of the labors of Herakles, from Greek Augeias, like the stable of Augeas, king of Elis, which contained 3,000 oxen and had gone uncleansed for 30 years. Herakles purified it in one day by turning the river Alpheus through it.
